The privacy implications of their respective offerings are quite different. Gmail actively scans your email looking for keywords, while iCloud is not ad-supported and does not read your email. AdWords makes your web searches follow you on the sites that you visit; iAd does not allow your Internet activities to affect the ads that are displayed. Google's servers log what I searched for, and Apple's do not. Etc.
The privacy implications of their respective offerings are quite different. Gmail actively scans your email looking for keywords, while iCloud is not ad-supported and does not read your email. AdWords makes your web searches follow you on the sites that you visit; iAd does not allow your Internet activities to affect the ads that are displayed. Google's servers log what I searched for, and Apple's do not. Etc.